Prepare wire for 3 Gang

The Jacket (Sheathing) Strip (1/2")

You should cut back the outer jacket so that only about 1/2 inch to 1 inch of the sheathing remains inside the box.

Gather together all of the ground wires.

Crimp sleeve about 8 inches back to secure them together.  

Twist at the crimp to get about two inches back.

Cut one of the ground wires back to the crimp.

Tie together all neutral wires with a wire nut and make a twist that it goes about two inches back.

Stuff everything together in the Box